In a conventional turntable system for a record player of the type arranged to evacuate the air between the turntable body and the phonograph record placed on the turntable body, a turntable assembly having main and sub turntables is used because the air on the upper surface of the turntable assembly is led through passageways provided between the main and sub turntables to a duct which is made in a stationary shaft of the sub turntable. This conventional turntable assembly is complex in structure because it comprises man and sub turntables and auxiliary elements such as sealing pads on the surface of the main turntable, resulting in a high manufacturing cost.
The inventor of the present invention devised a new turntable system prior to the present invention which new turntable system is simple in construction. According to the new turntable system a rotary spindle is received in a bearing, and a turntable body is telescopically engaged, at its center hole with the spindle so as to rotate with the spindle. The spindle has a longitudinal passageway therein, and a plurality of passageways in radial directions, which plurality of passageways communicate with the longitudinal passageway at the top and the bottom of the longitudinal passageway. In other words, most of the spindle portions have a cylindrical shape, and the outside of the cylinder communicates with the inside of the same via the radial and longitudinal passageways. The turntable body of the previous invention has a circular recess around the center hole thereof, where the spindle has a projection arranged to be fitted in a center hole of a phonograph record. The turntable also has a plurality of grooves extending radially from the circular recess, and thus the air on the upper surface of the turntable is led via the grooves, the circular recess, the upper radial passageways, the longitudinal passageway and the lower radial passageways to the outside of the spindle. Namely, the lower radial passageways or openings of the spindle communicate with a suitable conduit communicating with a vacuum source, such as a vacuum pump. The diameter of the projection of the spindle is fixed to be less than about 7.15 millimeters to be fitted in the center hole of a record. For this reason, the inner diameter of the above-mentioned radial passageways as well as the number of the radial passageways are restricted by the outer diameter of the upper portion, i.e. the projection, of the spindle. Accordingly, the cross-sectional area of the upper passageways cannot be made large. As is well known, in order to obtain a high rate of airflow it is necessary to provide a large cross-sectional area of the passageway, and the airflow rate directly affects the attracting force applied to the photograph record. Especially, when a phonograph record is warped or bent, it is necessary to attract the phonograph record with a high rate of airflow to make it flat and to securely support the phonograph record on the turntable.
In addition, since the outer diameter of the spindle is fixed and is small, it is difficult to machine the same to make passageways therein. This results in a high manufacturing cost.